The present invention relates to a fan-folded type ribbon cartridge for use in a printer.
In general, what are called fan-folded type ribbon cartridges in which an ink ribbon is regularly folded with a constant width and is enclosed in a cartridge casing are constructed as follows: namely, the ink ribbon is regularly folded in a zigzag line and is enclosed in the enclosing space provided in the central portion of a cartridge casing. A part of this ink ribbon is pulled out to the outside from the pull-out port which is protrudingly formed at one end of the cartridge casing. Then the ink ribbon is again taken into the cartridge casing from the take-in port which is likewise protrudingly formed at the other end of the cartridge casing. In order to prevent the ink ribbon from being erroneously drawn in the overlapped state when the ink ribbon is pulled out from the enclosing space in the cartridge casing, hitherto, projections are formed on the bottom and top surfaces of the cartridge casing, near the outlet of the enclosing space such that they face each other, and the gap between the above-mentioned projections is set to be smaller than the width of the ink ribbon. With this arrangement, the ink ribbon is hooked by the projections, thereby realizing a smooth ribbon feed.
However, in such a conventional system, an ink ribbon which has been used almost until its life, cannot be held by those pair of projections due to various reasons such as decrease in width dimension of the ink ribbon because of the tension applied for a long time, reduction in rigidity of the base material of the ink ribbon as a result of the repeated impacts of the printing elements, and so forth. Consequently, problems are encountered such as an overlapping pull out of the ink ribbon, falling down or twisting of the ribbon in the cartridge casing, and folding of the ink ribbon when the ink ribbon is being pulled out from the enclosing space of the cartridge casing.